Oxidation of CO in the presence of SO2 using gold supported on La2O3/TiO2 nanofibers

Abstract

Commercial catalysts currently available for catalytic incineration of sulfur compounds to SO2 in Claus tail gas do not engender complete oxidation of CO to CO2. This limitation thus prevents implementation of catalytic incineration in a growing number of jurisdictions which require complete CO oxidation. The aim of this study is therefore to develop a catalyst for CO oxidation which is effective in the presence of SO2 and water over a temperature range of 573–873K, which is the typical adiabatic temperature range for Claus tail gas incineration. In this research, two Au–La2O3–TiO2 nano-catalysts have been prepared using, in one case, deposition of Au and La2O3 on TiO2 nano-materials and, in a second case, by deposition of Au on a co-precipitated TiO2–La2O3 nano-material. The synthesized catalysts were characterized using electron microscopy, X-ray photoelectron spectroscopy, powder X-ray diffraction, and infrared spectroscopy. The resulting materials showed very high CO conversion above 323K and remained active over prolonged periods in the presence of SO2 and other sulfur compounds. The very high catalytic activity of the co-precipitated catalyst was attributed to the presence of cationic Au and a low level of sulfate formation on the nano-fiber support.